Farmers’ Management Practices and Grain Yield of Rice in Response to Different Water Environments in Kamping Puoy Irrigation Rehabilitation Area in Northwest Cambodia

Abstract

The farmers’ management practices and grain yield were examined in the consecutive 4 cropping seasons from wet season rice (WSR) in 2008 to dry season rice (DSR) in 2010 across upstream, midstream and downstream fields, along two secondary drainage canals (located either upstream or downstream side along the main canal) in the Kamping Puoy Irrigation Rehabilitation area (KPIR). In WSR, standing water depth was much deeper in downstream fields where medium and late maturing varieties were planted from May than in upstream fields where early and early medium maturing varieties were planted later (mostly in July and August). In DSR there was less difference in water conditions between upstream and downstream fields and variation in planting and harvesting time was small. As the area percentage of fields where DSR was introduced increased from 2008 (54%) to 2010 (100%), planting time in WSR was later (e.g., from May to July) with declining proportion of dry seeding method and mid-season tillage. Grain yield was low in DSR, particularly in 2010 (287 and 247 g m-² in 2009 and 2010 on average, respectively), due to insufficient weed control and small amount of fertilizer, and the yield was lowest in fields which practiced DSR for the first time. Grain yield in WSR (286 and 291 g m-² in 2008 and 2009 respectively) increased by transplanting, use of high yielding Raing Chey variety, and application of a larger amount of N chemical fertilizer. These findings indicated that the agriculture extension support to farmers, particularly in DSR, is a key important factor for rice yield improvement in KPIR.     

Estimation of supplementary water to paddy fields in the lower Mekong River basin during the dry season

Efficient management of water resources in paddy fields requires an understanding of the volume of supplementary water used. However, quantifying the volume is laborious due to the large amount of data that must be collected and analyzed. The purpose of our study was to estimate the volume of supplementary water used in paddy fields, based on several years of available statistical data, and to provide information on how much water can be supplied to paddy fields in each target area. In this study, the lower Mekong River basin of northeast Thailand, Laos, and Cambodia was selected as the study area. In the first step, we used agricultural statistics for each country, rainfall data acquired from the Mekong River Commission Secretariat (MRCS), and the value of virtual water required per unit of rice production. Because several years of data were used for dry season harvested areas and rice production in each country, the supplementary water to paddy fields in each province was calculated using virtual water and rainfall. This method made it possible to estimate changes in supplementary water in each province. Through this study, the supplementary water to paddy fields during the dry season in three countries was approximated from the minimum number of data sets. Moreover, for cases in which it is not possible to procure agricultural water use data for a hydrological model simulation, an alternative solution is proposed.     

The effect of long-term feeding of fresh and ensiled cassava (Manihot esculenta) foliage on gastrointestinal nematode infections in goats

The benefit of long-term feeding of fresh or ensiled cassava foliage on gastrointestinal parasite in goats was evaluated. Eighteen male goats (15.15 ± 2.83kg and between 4–6months) were randomly allocated into three treatments supplemented with 200g of wheat bran head⁻¹ day⁻¹. All groups were fed ad-libitum on either grass (CO), fresh cassava (CaF) or ensiled cassava foliage (CaS). At the beginning of the trial, each goat was inoculated with 3000 L3 containing ≈50% Haemonchus contortus. Individual LWt, FEC and PCV were measured at weekly intervals for 10weeks. At the termination of the experiment all goats were slaughtered for worm recovery and enumeration. The goats in CaF and CaS had similar weight gains while those in CO lost weight (p < 0.05) through the trial. FEC in CaF and CaS were lower (p < 0.05) than CO during the patency of parasite infections, but there was no difference between CaF and CaS goats. PCV of all groups decreased from above 30% to around 25% at the end of the trial. The compositions of established worm burdens were mainly H. contortus (19–40%) and Trichostrongylus colubriformis (55–76%). TWB did not differ among the groups, however, CaS significantly reduced H. contortus burdens, as compared to CaF and CO (p ≤ 0.005). Thus, ensiled cassava foliage reduced the H. contortus population while the fresh foliage only reduced worm fecundity.     

柬埔寨不同移栽期对烤烟生长和产质量的影响

为确定适宜移栽期,提高柬埔寨烤烟产质量,于2015—2016年采用烤烟品种‘粤烟98’和‘云烟87’,设置3个移栽期梯度试验,调查烤烟生长发育及产质量。试验结果表明：与当地习惯移栽期相比,2个品种提早10天移栽,整体农艺性状提高,烟株高度、叶数、腰叶长度分别增加4.5 cm、1片、0.6~2.0 cm;经济性状显著提高,每公顷烟叶产量、产值、每公斤均价、上等烟比例分别增加117.0~121.5 kg、6682.5~6905.7元、1.7~2.1元、4.5~12.5个百分点,差异达显著水平;烤后烟叶外观质量得分提高0.5~1.5分,糖碱比和氮碱比提高、整体协调性转好;而推迟10天移栽的处理,烟株农艺性状、烟叶经济性状、原烟外观和内在品质则表现出相反趋势。因此,在柬埔寨磅湛省烤烟生产上,12月初为最佳移栽期,即在当前季节提前10天移栽有利于烟株生长和烟叶产质量提高。     

Evaluation of alternative strategies to prevent Newcastle disease in Cambodia

Velogenic viscerotropic Newcastle disease (vvNCD), which is endemic in Cambodia, can be prevented in theory by a combination of biosecurity and immunization of broiler flocks. The relative contribution of appropriate biosecurity and effective vaccination was quantified at the farm level, applying realistic projections for capital investment, fixed and variable production costs and losses following infection. Non-protected broiler flocks generate a loss when the probability of vvNCD infection exceeds 0.4. Applying both biosecurity and effective vaccination would sustain profitability up to a probability of exposure of 1.0. The benefit to cost ratios for alternative strategies were evaluated for a range of probabilities of exposure to vvNCD extending from 0.1 to 1.0. The benefit-to-cost ratio for biosecurity exceeded unity at a risk of exposure exceeding 0.1, and 0.2 for vaccination and the combination of vaccination and biosecurity respectively. A sensitivity analysis demonstrated that the efficiency of protection, feed cost, and financial consequences of infection markedly affected the projected benefit-to-cost ratios associated with alternative methods of prevention.     

Seasonal fluctuation of groundwater in an evergreen forest, central Cambodia: experiments and two-dimensional numerical analysis

This study of a water cycle was conducted in an evergreen forest located in the Mekong River Basin in central Cambodia. At the observation site, we measured the dynamics of the spatial distribution of groundwater levels. The groundwater movement was analyzed two-dimensionally using boundary conditions and parameters that had been observed in the field. The climate in the research area is dominated by two seasons, which occur annually: a rainy and a dry season. The groundwater levels are generally high during the rainy season and low during the dry season. Groundwater levels were measured along a stream, which flowed through the study site. The streambed was visible at the head of the stream in January. At the next downriver well point, the streambed appeared in March. Finally, it became visible at all well points in April, meaning that surface runoff had disappeared temporarily and instead flowed underground during the ensuing dry period. Groundwater levels of the studied lateral flow perpendicular to the stream that seeped and infiltrated into the stream were 1.2–2.5 m deep (in April), which was the lowest level recorded for the year. During that period, the depth of the groundwater of the studied lateral flow fell by as much as 56 mm per month. In addition, the lateral flow groundwater infiltrated into groundwater of the stream during that period. The groundwater level fluctuation was estimated based on a two-dimensional analysis of lateral flow perpendicular to the stream using a numerical simulation model with soil physical parameters and observed boundary conditions. The observations of ground water fluctuations were well reproduced. Deep seepage of groundwater was estimated using a uniform boundary condition that allowed efflux through the bottom, estimated as being approximately 30 mm per year. The simulated deep seepage rate was considered plausible considering other hydrological components such as soil water storage fluctuation.     

Dutiful tourism: Encountering the Cambodian genocide

This paper considers contemporary international tourism to a genocide museum in Phnom Penh, Cambodia. It argues that existing theorisations of ‘dark tourism’ are inadequate for the task of understanding the motivations, actions and experiences of visitors in such a place, or of such sites as contested international institutions. The paper is concerned with the ways in which visiting practices encouraged at the Tuol Sleng Museum of Genocide Crimes in the immediate post‐genocide period (the 1980s) continue to affect visiting practices in the present. Moreover, the absence of familiar curatorial practices and technologies of interpretation leads contemporary visitors to conceive of the space of the museum and their visit in unexpected ways. The dutiful comportment of visitors at Tuol Sleng both supports and challenges the moral geographies enacted by contemporary travel.     

柬埔寨吴哥植物资源调查研究

柬埔寨位于东南亚中南半岛南部,覆盖大面积热带雨林,是个美丽富饶的国家,被称为"富贵真腊"。通过参考有关资料和实地勘察,调查柬埔寨吴哥的植物资源种类。结果表明:柬埔寨的植物资源丰富、种类繁多且分布广泛,约有1.5万种;山区分布着常绿阔叶林和松林,北部平原有龙脑香林,东部平原有草地和落叶林,沿海分布着红树林。分析吴哥的植物调查情况,提出应进行合理开发和生态保护。     

The violence of homelessness: Exile and arbitrary detention in Cambodia's war on the poor

This article examines the plight of homeless peoples in Phnom Penh, Cambodia as a consequence of their enmeshment in a new logic of urban governance being rolled out by city officials and municipal planners. The widespread adoption of neoliberal economics has resulted in a globalised version of urban entrepreneurialism, to which Phnom Penh is a participant. The (re)production of enterprise zones, cultural spectacles, waterfront development, and privatised forms of local governance all reflect the powerful disciplinary effects of interurban competition as cities aggressively engage in mutually destructive place‐marketing policies. Against this neoliberal backdrop, the ongoing pattern of violence utilised by municipal authorities against homeless peoples in Phnom Penh is part of a gentrifying process that the local government has dubbed a ‘beautification’ agenda. Of particular concern is how city officials have begun actively promoting the criminalization of the urban homeless and poor through arbitrary arrests and illegal detention, holding them in so‐called re‐education or ‘rehabilitation’ centres. Yet these centres are not what they seem. Such euphemisms attempt to mask the systemic abuse of marginalised peoples who are deemed to present Phnom Penh in a negative light and are consequently unwanted on the streets of the capital city.